1. Field
The following description relates to a technology to estimate a location of a terminal, and more particularly, to a technology to estimate a location of a terminal by using signals transmitted from base stations.
2. Description of Related Art
Research has increased regarding a multi-cell communication environment including a plurality of cells. For example, the multi-cell communication environment may include a multi-macro cell communication environment including at least two macro cells, a multi-small cell communication environment including a plurality of small cells, such as picocells and femtocells, and a layer-cell communication environment including at least one macrocell and at least one small cell.
Location information of a terminal in a communication system of the multi-cell communication environment may be used for various purposes. For example, the location information of the terminal may be essential to provide location-based service, and may facilitate multi-node cooperative communication.
Also, an efficient method of estimating the location of the terminal includes detecting the location of the terminal based on an identification (ID) of a service cell that serves the terminal. However, the method of detecting the location of the terminal based on the ID of the service cell may not accurately detect the location of the terminal. There has been an attempt to apply Time of Arrival (ToA)-based location estimating method to improve accuracy, or an attempt to attach a Global Positioning System (GPS) receiver to a terminal. More specifically, the ToA-based location estimating method estimates the location of the terminal based on arrival time of signals received from the plurality of existing base stations, and when the GPS receiver is included in the terminal, the terminal reports its location to the base station.
However, the terminal sequentially measures arrival time of each of the received signals to perform the ToA-based location estimating method, and thus, power consumption of the terminal may increase. In addition, the base stations and the terminal require an accurately synthesized clock to accurately apply the ToA-based location estimating method, which leaves room for error and problems in application of the ToA-based location estimating method. Also, attaching the GPS receiver to the terminal may increase overall cost of the terminal.